Medical information processing apparatus and medical information processing method

ABSTRACT

A medical information processing apparatus according to an embodiment includes processing circuitry. The processing circuitry acquires a first index value obtained based on fluid analysis that is performed based on an image including a blood vessel of a subject, the first index value being related to blood flow at each of positions in the blood vessel. The processing circuitry acquires external information including a second index value related to blood flow at each of the positions in the blood vessel. The processing circuitry changes one of an arrangement direction of index values in a first graph and an arrangement direction of index values in a second graph in accordance with the other one of the arrangement directions. The processing circuitry displays the first graph and the second graph on a display unit such that the arrangement directions of the index values match each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division application of U.S. application Ser. No.15/724,793, filed Oct. 4, 2017, which is based upon and claims thebenefit of priority from Japanese Patent Application No. 2016-196802,filed on Oct. 4, 2016; the entire contents each of which areincorporated herein by reference.

FIELD

Embodiments described herein relate generally to a medical informationprocessing apparatus and a medical information processing method.

BACKGROUND

It is conventionally known that the causes of ischemic diseases oforgans are broadly divided into poor blood circulation and dysfunctionof organs themselves. For example, a stenosis, which is an example ofpoor blood circulation of a coronary artery, is a serious lesion thatcauses ischemic heart diseases, and there is a need to determine whetherto conduct drug treatment, stent treatment, or the like for the ischemicheart diseases. In recent years, as a diagnosis for performingevaluation of hematogenous ischemia in a coronary artery, there has beena recommended technique to measure myocardial fractional flow reserve(FFR) by using a pressure wire in coronary angiographic examination(coronary angiography: CAG) using a catheter.

Alternatively, there is a known technique to non-invasively performevaluation of hematogenous ischemia in a coronary artery by usingmedical images of a heart, which are collected by, for example, amedical image diagnostic apparatus, such as an X-ray computer tomography(CT) apparatus, a magnetic resonance imaging (MRI) apparatus, or anultrasonic diagnostic apparatus. In this manner, evaluation ofhematogenous ischemia is performed by various techniques and medicaltreatment is conducted according to the evaluation. In recent years,there is an increasing demand to evaluate an actual treatment effectbefore treatment is conducted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a configuration of amedical information processing system according to a first embodiment.

FIG. 2 is a diagram illustrating an example of a configuration of amedical information processing apparatus according to the firstembodiment.

FIG. 3 is a diagram for explaining an example of a process by a controlfunction according to the first embodiment.

FIG. 4 is a diagram for explaining a time phase used for fluid analysisaccording to the first embodiment.

FIG. 5A is a diagram for explaining generation of a graph by ageneration function according to the first embodiment.

FIG. 5B is a diagram for explaining generation of a graph by thegeneration function according to the first embodiment.

FIG. 6 is a diagram illustrating an example of a graph displayed by anFFR measurement apparatus in FFR measurement using a pressure wire.

FIG. 7A is a diagram for explaining an example of determination of anarrangement direction of index values by a determination functionaccording to the first embodiment.

FIG. 7B is a diagram for explaining an example of determination of thearrangement direction of the index values by the determination functionaccording to the first embodiment.

FIG. 8A is a diagram for explaining an example of display informationdisplayed by a display control function according to the firstembodiment.

FIG. 8B is a diagram for explaining an example of the displayinformation displayed by the display control function according to thefirst embodiment.

FIG. 9 is a flowchart illustrating the flow of a process performed bythe medical information processing apparatus according to the firstembodiment.

FIG. 10A is a diagram for explaining an example of determination of anarrangement direction of index values by a determination functionaccording to a second embodiment.

FIG. 10B is a diagram for explaining an example of determination of thearrangement direction of the index values by the determination functionaccording to the second embodiment.

FIG. 11A is a schematic diagram illustrating an example of a change in adisplay orientation by a determination function according to the secondembodiment.

FIG. 11B is a schematic diagram illustrating an example of a change inthe display orientation by the determination function according to thesecond embodiment.

FIG. 12 is a diagram illustrating an example of display of a graph by adisplay control function according to the second embodiment.

FIG. 13 is a diagram illustrating an example of display of a graph bythe display control function according to the second embodiment.

FIG. 14 is a diagram for explaining an example of display by the displaycontrol function according to the second embodiment.

FIG. 15 is a diagram illustrating an example of display by the displaycontrol function according to the second embodiment.

DETAILED DESCRIPTION

According to an embodiment, a medical information processing apparatusincludes processing circuitry. The processing circuitry is configured toacquire a first index value obtained based on fluid analysis that isperformed based on an image including a blood vessel of a subject, thefirst index value being related to blood flow at each of positions inthe blood vessel. The processing circuitry is configured to acquireexternal information including a second index value related to bloodflow at each of the positions in the blood vessel. The processingcircuitry is configured to change one of an arrangement direction ofindex values in a first graph and an arrangement direction of indexvalues in a second graph in accordance with the other one of thearrangement directions, the first graph being a graph in which the firstindex value at each of positions in a long axis direction of the bloodvessel is plotted, and the second graph being a graph in which thesecond index value at each of the positions in the long axis directionof the blood vessel is plotted. The processing circuitry is configuredto display the first graph and the second graph on a display unit suchthat the arrangement directions of the index values match each other.

Embodiments of a medical information processing apparatus and a medicalinformation processing method according to the present application willbe described in detail below with reference to the accompanyingdrawings. The medical information processing apparatus and the medicalinformation processing method according to the present application arenot limited by the embodiments described below.

First Embodiment

A first embodiment will be described below. In the first embodiment, anexample will be described in which a technique according to thisapplication is applied to a medical information processing apparatus.Hereinafter, a medical information processing system including themedical information processing apparatus will be described as anexample. Furthermore, as an example, a case will be described in which ablood vessel in a heart is used as an analysis target.

FIG. 1 is a diagram illustrating an example of a configuration of themedical information processing system according to the first embodiment.As illustrated in FIG. 1 , the medical information processing systemaccording to the first embodiment includes an X-ray computer tomography(CT) apparatus 100, an image storage apparatus 200, and a medicalinformation processing apparatus 300.

For example, as illustrated in FIG. 1 , the medical informationprocessing apparatus 300 according to the first embodiment is connectedto the X-ray CT apparatus 100 and the image storage apparatus 200 via anetwork 400. The medical information processing system may be furtherconnected to a different medical image diagnostic apparatus, such as amagnetic resonance imaging (MRI) apparatus, an ultrasonic diagnosticapparatus, or a position emission tomography (PET) apparatus, via thenetwork 400.

The X-ray CT apparatus 100 collects CT image data (volume data) on asubject. Specifically, the X-ray CT apparatus 100 causes an X-ray tubeand an X-ray detector to rotate substantially around the subject todetect X-rays transmitted through the subject and collect projectiondata. The X-ray CT apparatus 100 generates time-series three-dimensionalCT image data based on the collected projection data.

The image storage apparatus 200 stores therein image data collected byvarious medical image diagnostic apparatuses. For example, the imagestorage apparatus 200 is implemented by a computer apparatus, such as aserver apparatus. In the first embodiment, the image storage apparatus200 acquires CT image data (volume data) from the X-ray CT apparatus 100via the network 400 and stores the acquired CT image data in a memoryprovided inside or outside the apparatus.

The medical information processing apparatus 300 acquires image datafrom various medical image diagnostic apparatuses via the network 400and processes the acquired image data. For example, the medicalinformation processing apparatus 300 is implemented by a computerapparatus, such as a workstation. In the first embodiment, the medicalinformation processing apparatus 300 acquires CT image data from theX-ray CT apparatus 100 or the image storage apparatus 200 via thenetwork 400, and performs various kinds of image processing on theacquired CT image data. The medical information processing apparatus 300displays, on a display or the like, the CT image data that has not beensubjected to the image processing or that has been subjected to theimage processing. The medical information processing apparatus 300 maybe installed in various locations. For example, the medical informationprocessing apparatus 300 may be installed in a CT room in which theX-ray CT apparatus 100 is installed, a catheter operation room in whichvarious operations using catheter are conducted, a radiologicinterpretation room in which radiologic interpretation of images isconducted, or the like. When the medical information processingapparatuses 300 are installed in a plurality of locations, the medicalinformation processing apparatus 300 is installed in each of thelocations.

FIG. 2 is a diagram illustrating an example of a configuration of themedical information processing apparatus 300 according to the firstembodiment. For example, as illustrated in FIG. 2 , the medicalinformation processing apparatus 300 includes an interface (I/F)circuitry 310, a memory 320, an input interface 330, a display 340, andprocessing circuitry 350.

The I/F circuitry 310 is connected to the processing circuitry 350, andcontrols transmission of various kinds of data and communicationperformed with various medical image diagnostic apparatuses or the imagestorage apparatus 200 connected via the network 400. For example, theI/F circuitry 310 is implemented by a network card, a network adapter, anetwork interface controller (NIC), or the like. In the firstembodiment, the I/F circuitry 310 receives CT image data from the X-rayCT apparatus 100 or the image storage apparatus 200, and outputs thereceived CT image data to the processing circuitry 350.

The memory 320 is connected to the processing circuitry 350 and storestherein various kinds of data. For example, the memory 320 isimplemented by a semiconductor memory device, such as a random accessmemory (RAM) or a flash memory, a hard disk, an optical disk, or thelike. In the first embodiment, the memory 320 stores therein CT imagedata received from the X-ray CT apparatus 100 or the image storageapparatus 200. Furthermore, the memory 320 stores therein a processingresult obtained by the processing circuitry 350.

The input interface 330 is connected to the processing circuitry 350,converts an input operation received from an operator into an electricsignal, and outputs the electric signal to the processing circuitry 350.For example, the input interface 330 is implemented by a trackball, aswitch button, a mouse, a keyboard, a touch panel, or the like.

The display 340 is connected to the processing circuitry 350 anddisplays various kinds of information and various kinds of image dataoutput from the processing circuitry 350. For example, the display 340is implemented by a liquid crystal monitor, a cathode ray tube (CRT)monitor, a touch panel, or the like.

The processing circuitry 350 controls each of the components included inthe medical information processing apparatus 300, in accordance with aninput operation that is received from an operator via the inputinterface 330. For example, the processing circuitry 350 is implementedby a processor. In the first embodiment, the processing circuitry 350stores CT image data output from the I/F circuitry 310 in the memory320. Furthermore, the processing circuitry 350 reads CT image data fromthe memory 320 and displays the CT image data on the display 340.

With this configuration, the medical information processing apparatus300 according to the first embodiment can improve the visibility of agraph of an index related to blood flow. Specifically, the medicalinformation processing apparatus 300 determines a display orientation ofthe graph of the index related to blood flow based on externalinformation, and displays the graph in the determined orientation toimprove the visibility of the graph. The medical information processingapparatus 300 is able to perform a process of determining the displayorientation in accordance with an environment in which the graph is tobe displayed, and a process of determining the display orientation inaccordance with other graphs to be displayed for comparison. Theprocesses are sequentially described below.

To perform the processes as described above, as illustrated in FIG. 2 ,the processing circuitry 350 in the medical information processingapparatus 300 according to the first embodiment executes a controlfunction 351, a generation function 352, a determination function 353,and a display control function 354. The processing circuitry 350 is oneexample of processing circuitry in the appended claims.

The control function 351 controls the entire medical informationprocessing apparatus 300. For example, the control function 351 controlsvarious processes corresponding to electric signals received from theinput interface 330. As one example, the control function 351 controlsacquisition of CT image data via the I/F circuitry 310, storage of theacquired CT image data in the memory 320, or the like. Furthermore, forexample, the control function 351 controls read of CT image data storedin the memory 320 and generation of a display image from the read CTimage data. As one example, the control function 351 performs variouskinds of image processing on CT image data to generate an image of ablood vessel. For example, the control function 351 performs imageprocessing on CT image data to generate a volume rendering image, acurved multi planer reconstruction (CPR) image, a multi planerreconstruction (MPR) image, a stretched multi planer reconstruction(SPR) image, or the like. Furthermore, the control function 351 acquiresan index value related to blood flow at each of positions in a bloodvessel, where the index value is obtained based on fluid analysis thatis performed based on an image including the blood vessel of a subject.The control function 351 is able to acquire the index value byperforming the fluid analysis, and is also able to acquire a result ofthe fluid analysis via the network 400. Hereinafter, a case will bedescribed in which the control function 351 performs the fluid analysis.

The control function 351 performs fluid analysis based on CT image data.Specifically, the control function 351 performs fluid analysis based onan image including a blood vessel of a subject, and obtains an indexvalue related to blood flow at each of positions in the blood vessel.More specifically, the control function 351 extracts time-seriesblood-vessel shape data, which indicates the shape of a blood vessel,from three-dimensional CT image data. For example, the control function351 reads CT image data in a plurality of time phases, which iscollected over time, from the memory 320, and performs image processingon the read CT image data in the plurality of time phases to extract thetime-series blood-vessel shape data.

Here, the control function 351 sets a target region, for which an indexvalue related to blood flow is to be calculated, in a blood vesselregion included in CT image data. Specifically, the control function 351sets the target region in the blood vessel region in accordance with aninstruction or image processing performed by an operator via the inputinterface 330. Then, the control function 351 extracts, as theblood-vessel shape data of the set target region, the centerline of theblood vessel (coordinate information on the centerline), cross-sectionalareas of a blood vessel and a lumen in a cross section perpendicular tothe centerline, a distance from the centerline to an inner wall and adistance from the centerline to an outer wall in a cylinder direction inthe cross section perpendicular to the centerline, or the like from theCT image data. The control function 351 may extract various other kindsof blood-vessel shape data depending on analysis techniques.

Furthermore, the control function 351 sets an analysis condition of thefluid analysis. Specifically, the control function 351 sets, as theanalysis condition, a physical property value of blood, a condition ofiterative calculation, a default value of analysis, or the like. Forexample, the control function 351 sets, as the physical property valueof blood, a viscosity of blood, a density of blood, or the like.Furthermore, the control function 351 sets, as the condition ofiterative calculation, the maximum number of times of iteration in theiterative calculation, a relaxation coefficient, an allowable value of aresidual error, or the like. Moreover, the control function 351 sets, asthe default value of analysis, a default value of a flow rate, apressure, a fluid resistance, a pressure boundary, or the like. Variousvalues used by the control function 351 may be incorporated in thesystem in advance, or may be defined interactively by an operator.

The control function 351 calculates an index related to blood flow of ablood vessel through fluid analysis using image data including the bloodvessel (for example, a coronary artery or the like). Specifically, thecontrol function 351 performs fluid analysis using the blood-vesselshape data and the analysis condition, and calculates the index relatedto the blood flow in the target region of the blood vessel. For example,the control function 351 calculates an index, such as a pressure, ablood flow rate, a blood flow velocity, a vector, or a shear stress, ateach of predetermined positions in the blood vessel, based on theblood-vessel shape data, such as the contour of the lumen, the outerwall of the blood vessel, the cross-sectional area of the blood vessel,or the centerline of the blood vessel, and based on the set condition,such as the physical property value of blood, the condition of iterativecalculation, or the default value of analysis. The control function 351also calculates a temporal change in the index, such as the pressure,the blood flow rate, the blood flow velocity, the vector, or the shearstress, by using a temporal change in the blood-vessel shape data, suchas the contour of the lumen or the outer wall of the blood vessel, thecross-sectional area of the blood vessel, or the centerline of the bloodvessel.

FIG. 3 is a diagram for explaining an example of a process by thecontrol function 351 according to the first embodiment. As illustratedin FIG. 3 , for example, the control function 351 extracts blood-vesselshape data including the coordinates of the centerline and informationon a cross section with respect to a left anterior descending artery(LAD) as a target region, from three-dimensional CT image data includingan aorta and a coronary artery. Furthermore, the control function 351sets an analysis condition for analysis for the extracted LAD as thetarget. Then, the control function 351 performs fluid analysis using theextracted blood-vessel shape data on the LAD and the set condition tocalculate the index, such as the pressure, the blood flow rate, theblood flow velocity, the vector, or the shear stress, at each ofpredetermined positions along the centerline from the inlet boundary tothe outlet boundary of the target region LAD, for example. That is, thecontrol function 351 calculates a distribution of the pressure, theblood flow rate, the blood flow velocity, the vector, the shear stress,or the like for the target region.

As described above, the control function 351 extracts pieces ofblood-vessel shape data from each of the pieces of the CT image data inthe plurality of time phases collected over time, and performs fluidanalysis using the pieces of the extracted blood-vessel shape data inthe plurality of time phases and the analysis condition to calculate theindex related to the blood flow. Here, the control function 351calculates an analysis result with higher accuracy by using CT imagedata in a plurality of time phases in which the cardiac phase fallswithin a predetermined range.

FIG. 4 is a diagram for explaining the time phase used for the fluidanalysis according to the first embodiment. In FIG. 4 , the uppersection indicates a heart rate, the middle section indicates movement ofthe heart, and the lower section indicates the area of the coronaryartery. Furthermore, in FIG. 4 , the horizontal direction indicatestime, and, temporal changes in the heart rate, the movement of theheart, and the area of the coronary artery are illustrated in anassociated manner. For example, the control function 351 performs fluidanalysis by using CT image data in cardiac phases included in the rangeof cardiac phases of 70% to 99%. As illustrated in FIG. 4 , the cardiacphases of 70% to 99% are time phases in which the heart does not movemuch and the area of the coronary artery changes largely. The heartmoves with contraction and expansion, and the movement of the heart isstable in the latter half of a diastole (in the cardiac phases of 70% to99%) as illustrated in the middle section of FIG. 4 . That is, thecontrol function 351 can use CT image data including little movementswith the heartbeat, by using the CT image data in the cardiac phaseincluded in the cardiac phases of 70% to 99% in which the movement ofthe heart is stable.

Furthermore, as illustrated in the lower section of FIG. 4 , the area ofthe coronary artery becomes the largest in the cardiac phase of around70% and becomes the smallest in the cardiac phase of around 99%. This isbecause blood starts to flow into the coronary artery in the cardiacphase of around 70% and then flows out as the cardiac phase approaches99%. The control function 351 calculates an analysis result with higheraccuracy by using the CT image data in the plurality of time phases inthe range of the cardiac phases of 70% to 99% such that a change in thearea of the coronary artery can be included as much as possible.

Furthermore, the control function 351 calculates a myocardial fractionalflow reserve (FFR) based on a distribution of a pressure in the targetregion. Specifically, the control function 351 calculates an FFR, whichis an index to estimate how much blood flow is inhibited by a lesion,based on pressures on the upstream side and the downstream side of apredetermined position in a blood vessel (for example, a lesion site,such as a stenosis or a plaque). The control function 351 according tothe present application is able to calculate various pressure indexes asthe FFR.

The definition of the FFR is described below. As described above, theFFR is an index for estimating how much blood flow is inhibited by alesion (for example, a stenosis or a plaque). The FFR is defined by aratio of a flow rate that is obtained when there is no lesion to a flowrate that is obtained when there is a lesion, and is calculated byExpression (1) below. In Expression (1), “Qn” denotes the flow rate thatis obtained when there is no lesion, and “Qs” denotes the flow rate thatis obtained when there is a lesion.

$\begin{matrix}{{FFR} \equiv \frac{Qs}{Qn}} & (1)\end{matrix}$

As indicated by Expression (1), for example, the FFR is defined by theequation of division of “Qs” by “Qn”. In general, to calculate the FFR,adenosine is administered to a subject to obtain the maximum hyperemiastate (stressed state), so that the relationship between the flow rateand the pressure in a blood vessel can be represented as a proportionalrelationship and the FFR can be replaced with the definition of apressure. That is, by representing the relationship between the flowrate and the pressure in the blood vessel as a proportionalrelationship, Expression (1) can be represented as Expression (2) below.In Expression (2), “Pa” denotes a pressure on the upstream side of alesion, and “Pd” denotes a pressure on the downstream side of thelesion. Furthermore, “Pv” denotes a pressure of the right atrium towhich venous blood flows from all over the body.

$\begin{matrix}{{{FFR} \equiv \frac{Qs}{Qn}} = \frac{{Pd} - {Pv}}{{Pa} - {Pv}}} & (2)\end{matrix}$

For example, by representing the relationship between the flow rate andthe pressure in a blood vessel as a proportional relationship, “Qs” maybe represented as “Pd-Pv” and “Qn” may be represented as “Pa-Pv” asindicated in Expression (2). That is, the FFR is represented by a ratiobetween values that are obtained by subtracting the pressure at the baseline of the blood vessel from the pressure on the upstream side of thelesion and from the pressure on the downstream side of the lesion.

In the stressed state in which adenosine is administered to the subject,it is possible to handle the values such that “Pa>>Pv” and “Pd>>Pv”;therefore, Expression (2) may be regarded as Expression (3) below.

$\begin{matrix}{{{FFR} \equiv \frac{Qs}{Qn}} = {\frac{{Pd} - {Pv}}{{Pa} - {Pv}} \approx \frac{Pd}{Pa}}} & (3)\end{matrix}$

Specifically, as illustrated in Expression (3), the FFR is calculated bythe equation of division of “Pd” by “Pa”. For example, the controlfunction 351 assigns the calculated pressure on the upstream side of thelesion and the calculated pressure on the downstream side of the lesionto the above-described Expression (3) to calculate the value of the FFRat each of positions in the blood vessel.

In the above-described calculation of the FFR, a case has been describedin which adenosine is administered to a subject to obtain a stressedstate so that the relationship between the flow rate and the pressure ina blood vessel can be represented as a proportional relationship and theFFR can be replaced with the definition of a pressure. However, in thecalculation of the FFR, it may be possible to employ a subject in aresting state and perform the calculation by replacing the FFR with thedefinition of a pressure. In this case, even in the resting state inwhich adenosine is not administered, the relationship between the flowrate and the pressure in a blood vessel is represented as a proportionalrelationship during a wave-free period in the cardiac cycle (a period inwhich vascular resistance is small and stable); therefore, the FFR iscalculated by using a pressure during the wave-free period in theresting state (hereinafter, the FFR calculated during the wave-freeperiod in the resting state may be described as an instantaneous FFR).

The instantaneous FFR is an index that contributes to reduce load on asubject because adenosine is not administered and that hascharacteristics (for example, it can reflect the effect of the heartmuscle or it can be measured even if a plurality of stenoses areobserved in a single blood vessel) which are not observed in the FFR;therefore, the instantaneous FFR is attracting attention in recentyears. In the calculation of the FFR using image data, CT image data inthe cardiac phases of 70% to 99% as described above is used as CT imagedata in the wave-free period. Specifically, the relationship between theflow rate and the pressure in a blood vessel is represented as aproportional relationship in the cardiac phases of 70% to 99%, andtherefore, if CT image data in these cardiac phases is used, it ispossible to calculate the FFR based on the pressure by theabove-described Expression (3) even when the CT image data is collectedfrom a subject in the resting state.

Furthermore, if a pressure “P0” at zero flow rate, which is the pressurein a blood vessel when the flow rate in the blood vessel is “0”, is usedas a base line to be subtracted from the pressure on the upstream sideof the lesion and the pressure on the downstream side of the lesion, thecontrol function 351 can more accurately express a proportionalrelationship between the flow rate and the pressure as compared to thecase where the pressure “Pv” of the right atrium is used as the baseline. In this case, the control function 351 assigns the pressure on theupstream side of the lesion site, the pressure on the downstream side ofthe lesion site, and the pressure at zero flow rate to Expression (4)below to calculate the value of the FFR at each of the positions in theblood vessel. In Expression (4), “Pa” denotes the pressure on theupstream side of the lesion (for example, a stenosis), and “Pd” denotesthe pressure on the downstream side of the lesion (for example, astenosis). Furthermore, in Expression (4), “P0” denotes the pressure atzero flow rate. The pressure at zero flow rate is estimated by searchingfor a pressure at which the flow rate and the flow velocity become zeroin the fluid analysis performed by the control function 351.

$\begin{matrix}{{{FFR} \equiv \frac{Qs}{Qn}} = \frac{{Pd} - {P\; 0}}{{Pa} - {P\; 0}}} & (4)\end{matrix}$

Here, the pressure “P0” at zero flow rate indicates a higher value than“Pv” in both of the stressed state and the resting state. This isbecause there is vascular resistance, and even in the state such as“P0>Pv”, blood does not flow and the flow rate becomes zero.Furthermore, “P0” during the wave-free period in the resting stateindicates a higher value than “P0” in the stressed state. This isbecause there is a difference in myocardial resistance between thestressed state and the resting state. For example, when a blood vesselexpands in the stressed state, the resistance decreases, so that thevalue of “P0” at the time the blood flow is zero becomes closer to thevalue of “Pv” as compared to the resting state. In contrast, in the caseof the resting state, the resistance is larger than the resistance inthe stressed state; therefore, the value of “P0” at the time the bloodflow is zero becomes larger than the value of “Pv”. Therefore, forexample, when CT image data during the wave-free period in the restingstate is used, the control function 351 calculates the FFR based on theexpression in which “P0” is taken into account as indicated byExpression (4).

When CT image data during the wave-free period in the resting state isused, the control function 351 may calculate the FFR by using theabove-described Expression (2). In this case, the control function 351assigns the pressure on the upstream side of the lesion site, thepressure on the downstream side of the lesion site, and “Pv” toExpression (2) to calculate the value of the FFR at each position in theblood vessel. Hereinafter, the above-described pressure indexes arecollectively referred to as the FFR.

Referring back to FIG. 2 , the generation function 352 generates a graphby using the index values related to the blood flow, which arecalculated by the control function 351. Specifically, the generationfunction 352 generates a graph indicating the index value at each ofpositions in the blood vessel. For example, the generation function 352generates a graph indicating the value of the FFR at each of positionsin the blood vessel. FIG. 5A and FIG. 5B are diagrams for explaininggeneration of a graph by the generation function 352 according to thefirst embodiment. FIG. 5A illustrates an example of a blood vessel onwhich the fluid analysis has been performed by the control function 351.FIG. 5B illustrates an example of the graph generated by the generationfunction 352.

For example, the generation function 352 acquires the values of the FFRat positions from a position on the branched side to a position on theperipheral side subjected to the fluid analysis in the blood vesselillustrated in FIG. 5A, and generates a graph as illustrated in FIG. 5Bby using the acquired values of the FFR. As one example, as illustratedin FIG. 5B, the generation function 352 generates a graph in which thehorizontal axis represents the positions in the blood vessel and thevertical axis represents the values of the FFR. In this case, thegeneration function 352 may generate a graph in which an auxiliary linefor evaluating the values of the FFR is added. For example, thegeneration function 352 generates a graph in which an auxiliary line isadded at the position of “0.8” as illustrated in FIG. 5B.

In the graph of the FFR generated by the generation function 352, thevalue gradually decreases from the branched side to the peripheral side;however, if a stenosis 51 has occurred in the blood vessel asillustrated in FIG. 5A for example, the value of the FFR largelydecreases at a corresponding position in the graph as indicated by acurved line L1. A medical doctor makes a diagnosis on whether to conductpercutaneous coronary intervention (PCI) or whether to perform drugtreatment, for example.

When displaying the graph as described above, the medical informationprocessing apparatus 300 according to the first embodiment determines adisplay orientation based on external information in order to improvethe visibility of the graph. As described above, a method using apressure wire is mainly used in the current FFR measurement, and asimilar graph is displayed in this method. However, in the method usinga pressure wire, it is often the case that the display orientation ofthe graph is opposite to the orientation of the graph illustrated inFIG. 5B due to the characteristics of the measurement method.

FIG. 6 is a diagram illustrating an example of a graph displayed on anFFR measurement apparatus in FFR measurement using a pressure wire. Forexample, in the FFR measurement using a pressure wire, as illustrated inthe upper section of FIG. 6 , a pressure wire 60 is first inserted untilthe peripheral side of a target region of a blood vessel and then pulledback while a sensor 61 measures a pressure at each of positions, so thatthe values of the FFR are calculated. In this manner, in the methodusing a pressure wire, values are displayed in real time based onresults acquired while the pressure wire is pulled back; therefore, thedisplay orientation of the graph is opposite to the orientationillustrated in FIG. 5B.

That is, in real-time display using a pressure wire, as indicated by acurved line L2 in FIG. 6 , the values of the pressure are acquired fromthe peripheral side and the graph is gradually generated based on theacquired values; therefore, the left side of the graph represents theperipheral side and the right side of the graph represents the branchedside. In this case, as illustrated in the lower section of FIG. 6 , thegraph is generated such that the value of the FFR gradually increasesfrom the peripheral side to the branched side and the value of the FFRlargely increases when the sensor 61 passes through a stenosis 52.

In contrast, when the FFR is calculated by fluid analysis, a graph isgenerated after the values of the FFR at the respective positions in theblood vessel are calculated; therefore, it is often the case that agraph in which the left side represents the branched side and the rightside represents the peripheral side as illustrated in FIG. 5B isgenerated. In this manner, when the FFR is calculated by fluid analysis,the display orientation of the graph may be opposite as compared to thecase where the FFR is measured by using a pressure wire. Therefore, whenan operator who is familiar with a graph using a pressure wire refers toa graph in the display orientation as illustrated in FIG. 5B, thevisibility may be reduced.

Therefore, the medical information processing apparatus 300 according tothe first embodiment determines a display orientation of a graph basedon a location in which the graph is used, an operator, or various kindsof external information, and displays the graph in the determineddisplay orientation to provide a familiar graph at any time and improvethe visibility of the graph.

Referring back to FIG. 2 , the determination function 353 determines, ina graph of an index value related to blood flow at each of positions inthe long axis direction of a blood vessel, an arrangement direction ofthe index values based on external information. Specifically, thedetermination function 353 is connected to an external apparatus, andacquires external information, which indicates an environment in whichthe index value is observed, from the external apparatus. That is, thedetermination function 353 acquires the external information from theexternal apparatus, and determines the environment in which the indexvalues are observed based on the external information. Then, in a graphin which the index values that are related to the blood flow at therespective positions in the long axis direction of the blood vessel andthat are obtained by the control function 351 are plotted, thedetermination function 353 determines the arrangement direction of theindex values based on the external information. That is, thedetermination function 353 determines the arrangement direction of theindex values based on the determined environment. For example, thedetermination function 353 determines the arrangement direction of theindex values in the graph based on information on a location in whichthe graph is displayed (a location in which the display 340 isinstalled), information on an operator, image information, a receptionsignal from the external apparatus, or information on a subject.

For example, in the case of a graph in which the vertical axisrepresents the index values and the horizontal axis represents thepositions in the long axis direction of the blood vessel, thedetermination function 353 determines on which one of the left side andthe right side of the graph the index value on the peripheral side ofthe blood vessel is to be arranged, based on the external information.In other words, the determination function 353 determines theenvironment in which the index values are observed based on the externalinformation, and determines on which one of the left side and the rightside of the graph the index value on the branched side of the bloodvessel is to be arranged.

The external information will be described below. As described above,the external information may be the information on a location in whichthe graph is displayed (a location in which the display 340 isinstalled), the information on an operator, the image information,information including the reception signal from the external apparatus,the information on the subject, or the like. Examples of the location inwhich the graph is displayed (the location in which the display 340 isinstalled) include a CT room, a catheter operation room, and aradiologic interpretation room. Furthermore, the information on anoperator is, for example, information on an operator who operates themedical information processing apparatus 300, and is information forspecifying a graph that is usually referred to. Moreover, examples ofthe image information include information indicating a type of an imageto be displayed together with the graph. Furthermore, examples of thereception signal from the external apparatus include a signal receivedfrom a medical image diagnostic apparatus, such as an FFR measurementapparatus that performs FFR measurement using a pressure wire, an X-rayCT apparatus, or an angiography apparatus. Moreover, examples of theinformation on a subject include information on a medical record. Thedetermination function 353 determines the environment in which the indexvalues are observed based on the external information as describedabove, and determines the display orientation in accordance with thedetermination result.

For example, if the information on a location is used, the informationon a location is stored in the memory 320 in advance when the medicalinformation processing apparatus 300 is installed, or the information ona location is input when an operator is authenticated, and thedetermination function 353 determines the display orientation by usingthe provided information. That is, the determination function 353 readsthe information on a location stored in the memory 320 and determinesthe arrangement direction of the index values in the graph based on theread information. Alternatively, the determination function 353determines the arrangement direction of the index values in the graphbased on the information on a location that is input when an operator isauthenticated.

FIG. 7A and FIG. 7B are diagrams for explaining determination of thearrangement direction of the index values by the determination function353 according to the first embodiment. For example, when the informationon a location in which the graph is displayed indicates a CT room or aradiologic interpretation room, the determination function 353 makes adetermination to display the graph such that the branched side isarranged on the left side as illustrated in FIG. 7A. In contrast, forexample, when the information on a location in which the graph isdisplayed indicates a catheter operation room, the determinationfunction 353 makes a determination to display the graph such that theperipheral side is arranged on the left side as illustrated in FIG. 7B.That is, in the case of the catheter operation room in which a graph isusually displayed by the FFR measurement apparatus, the determinationfunction 353 determines the display orientation to display a graph suchthat the peripheral side is arranged on the left side, similarly to agraph that is displayed by the FFR measurement apparatus. In contrast,in the case of the CT room or the radiologic interpretation room inwhich a graph is rarely displayed by the FFR measurement apparatus, thedetermination function 353 determines the display orientation to displaya graph such that the branched side is arranged on the left side,similarly to a graph that is displayed when the FFR is calculatedthrough fluid analysis.

In this manner, the determination function 353 determines the displayorientation of a graph such that the graph is displayed in accordancewith the display orientation of a graph that is usually referred to.That is, the determination function 353 determines the displayorientation of a graph based on the tendency of a graph to be referredto. The same applies when other kinds of information are used.

Furthermore, for example, when the information on an operator is used,the determination function 353 makes a determination to display a graphin which the branched side is arranged on the left side as illustratedin FIG. 7A for an operator who rarely refers to a graph displayed by theFFR measurement apparatus (who usually refers to a graph based on theFFR calculated through fluid analysis). In contrast, the determinationfunction 353 makes a determination to display a graph in which theperipheral side is arranged on the left side as illustrated in FIG. 7Bfor an operator who usually refers to a graph displayed by an FFRmeasurement apparatus (who rarely refers to a graph based on the FFRcalculated through fluid analysis).

Here, the operator may be identified based on operator information thatis input at the time of authentication, for example. In this case, forexample, the determination function 353 identifies the operator based oninformation on professional affiliation, a role, or the like of theoperator, which is input at the time of authentication. Furthermore, forexample, it may be possible to store information in which the displayorientation is set for a specific individual in the memory 320 inadvance, and cause the determination function 353 to determine thedisplay orientation by reading the display orientation set in advancefrom information on the operator input at the time of authentication.

Alternatively it may be possible to install a camera in each room, andidentify the operator from image information on the operator captured bythe camera. In this case, for example, the determination function 353acquires an image captured by the camera and performs image processingon the acquired image to identify the operator. As one example, thedetermination function 353 performs processing, such as patternmatching, on the image and determines whether the captured operatorwears scrub suits or gloves. When the operator wears scrub suits orgloves, the determination function 353 determines that the operatorperforms a catheter operation and determines that the operator usuallyrefers to a graph displayed by the FFR measurement apparatus. Incontrast, when the operator does not wear scrub suits or gloves, thedetermination function 353 determines that the operator does not performan operation and determines that the operator rarely refers to a graphdisplayed by the FFR measurement apparatus.

Furthermore, for example, when the image information is used, thedetermination function 353 acquires image information to be referred toand determines whether the acquired image has high real-time property.For example, if an image to be referred to is a past image and acquiredfrom the image storage apparatus 200, the determination function 353determines that the real-time property of the image is low. In contrast,for example, when the acquisition time of an image to be referred tocorresponds to a current time and the image is a moving image directlyacquired from an angiography apparatus, the determination function 353determines that the real-time property of the image is high.

Then, in the case of the image with low real-time property, thedetermination function 353 makes a determination to display a graph inwhich the branched side is arranged on the left side as illustrated inFIG. 7A. In contrast, in the case of the image with high real-timeproperty, the determination function 353 makes a determination todisplay a graph in which the peripheral side is arranged on the leftside as illustrated in FIG. 7B.

Furthermore, for example, when the reception signal from the externalapparatus is used, the determination function 353 receives a signal fromthe external apparatus and determines, based on the received signal, asituation in which a graph is to be referred to. That is, thedetermination function 353 determines whether a graph displayed by theFFR measurement apparatus is likely to be referred to in the situation,based on the signal received from the external apparatus. As oneexample, when receiving a signal from the FFR measurement apparatus, thedetermination function 353 determines that a graph displayed by the FFRmeasurement apparatus is likely to be referred to in the situation, andmakes a determination to display the graph such that the peripheral sideis arranged on the left side as illustrated in FIG. 7B. Furthermore,when receiving a signal related to real-time processing from anangiography apparatus (for example, a signal indicating that fluoroscopyis conducted), the determination function 353 determines that a graphdisplayed by the FFR measurement apparatus is likely to be referred toin the situation, and makes a determination to display the graph suchthat the peripheral side is arranged on the left side as illustrated inFIG. 7B.

Moreover, for example, when the information on a medical record is used,the determination function 353 reads a past display orientation from amedical record, and determines a display orientation such that thedisplay orientation becomes the same as the read display orientation.That is, the orientation of the graph displayed in the past is input inthe medical record, and when fluid analysis is performed on the samesubject again, the determination function 353 determines the arrangementdirection such that the index values are arranged in the same directionas the orientation of the graph recorded in the medical record.

As described above, the determination function 353 determines asituation in which the graph is to be displayed by using various kindsof external information, and determines the display orientation of thegraph in accordance with the determined situation.

Referring back to FIG. 2 , the display control function 354 displays agraph, in which the index values are arranged in the arrangementdirection determined by the determination function 353, on the display340. For example, when the determination function 353 determines whetherthe display 340 is located in an operating room by using theabove-described various kinds of information, the display controlfunction 354 displays the peripheral side on the left side when thedetermination function 353 determines that the display 340 is located inthe operating room, whereas the display control function 354 displaysthe peripheral side on the right side when the determination function353 determines that the display 340 is located in other places. FIG. 8Aand FIG. 8B illustrate examples of display information displayed by thedisplay control function 354 according to the first embodiment. Forexample, the display control function 354 displays a graph in which thebranched side is arranged on the left side as illustrated in FIG. 8A, inaccordance with the determination performed by the determinationfunction 353. Furthermore, for example, the display control function 354displays a graph in which the peripheral side is arranged on the leftside as illustrated in FIG. 8B, in accordance with the determinationperformed by the determination function 353.

The display control function 354 is able to display an image togetherwith a graph. Specifically, the display control function 354 furtherdisplays a medical image indicating the arrangement direction of theindex values. For example, when displaying a graph in which the branchedside is arranged on the left side, the display control function 354displays an SPR image in which the branched side is arranged on the leftside as illustrated in FIG. 8A. In contrast, when displaying a graph inwhich the peripheral side is arranged on the left side, the displaycontrol function 354 displays an SPR image in which the peripheral sideis arranged on the left side as illustrated in FIG. 8B. The image to bedisplayed is not limited to the SPR image, but may be a volume renderingimage or a CPR image.

Next, the flow of a process performed by the medical informationprocessing apparatus 300 according to the first embodiment will bedescribed. FIG. 9 is a flowchart illustrating the flow of a processperformed by the medical information processing apparatus 300 accordingto the first embodiment. Step S101 and Step S102 in FIG. 9 are realizedby, for example, causing the processing circuitry 350 to call a programcorresponding to the control function 351 from the memory 320 andexecute the program. Furthermore, Step S103 is realized by, for example,causing the processing circuitry 350 to call a program corresponding tothe generation function 352 from the memory 320 and execute the program.Moreover, Step S104 and Step S105 are realized by, for example, causingthe processing circuitry 350 to call a program corresponding to thedetermination function 353 from the memory 320 and execute the program.Furthermore, Step S106 is realized by, for example, causing theprocessing circuitry 350 to call a program corresponding to the displaycontrol function 354 from the memory 320 and execute the program.

In the medical information processing apparatus 300 according to thefirst embodiment, the processing circuitry 350 first performs fluidanalysis using collected CT image data (Step S101), and calculates indexvalues (for example, the FFR) related to blood flow (Step S102). Then,the processing circuitry 350 generates a graph (Step S103).

Subsequently, the processing circuitry 350 acquires external information(Step S104), and determines a display orientation of the graph based onthe external information (Step S105). Thereafter, the processingcircuitry 350 displays the graph in the determined orientation (StepS106).

As described above, according to the first embodiment, the determinationfunction 353 determines, based on the external information, thearrangement direction of the values of the FFR in a graph indicating thevalues of the FFR at the respective positions in the long axis directionof the blood vessel. The display control function 354 displays, on thedisplay 340, the graph in which the values of the FFR are arranged inthe arrangement direction determined by the determination function 353.Therefore, the medical information processing apparatus 300 according tothe first embodiment can display a graph that is usually referred to,and therefore can improve the visibility of the graph.

Furthermore, according to the first embodiment, the vertical axis of thegraph represents the values of the FFR and the horizontal axisrepresents the positions in the long axis direction of a blood vessel.The determination function 353 determines on which one of the left sideand the right side of the graph the value of the FFR on the peripheralside of the blood vessel is to be arranged, based on the externalinformation. Therefore, the medical information processing apparatus 300according to the first embodiment can improve the visibility of thegraph that is mainly used at the moment.

Moreover, according to the first embodiment, the determination function353 determines the arrangement direction of the values of the FFR basedon the information on a location in which the graph is displayed, theinformation on an operator, the image information, the reception signalfrom the external apparatus, or the information on the subject.Therefore, the medical information processing apparatus 300 according tothe first embodiment can determine the display orientation of the graphbased on various situations, and therefore can display an appropriategraph in the various situations.

Furthermore, the display control function 354 according to the firstembodiment further displays a medical image indicating the arrangementdirection of the values of the FFR. Therefore, the medical informationprocessing apparatus 300 according to the first embodiment can visuallyindicate the display orientation of the graph, and therefore can furtherimprove the visibility.

Second Embodiment

While the first embodiment has been described above, various differentembodiments other than the above-described first embodiment isapplicable.

In the above-described first embodiment, a case has been described inwhich a graph in a landscape orientation is displayed. However, theembodiment is not limited to this example, and a graph may be displayedin arbitrary orientations. For example, the generation function 352 cangenerate a graph in which the horizontal axis represents the values ofthe FFR and the vertical axis represents the positions in the long axisdirection of a blood vessel. In this case, the determination function353 determines the display orientation accordingly.

For example, the determination function 353 according to a secondembodiment determines on which one of the upper side and the lower sideof a graph the value of the FFR on the peripheral side of a blood vesselis to be arranged, based on external information. FIG. 10A and FIG. 10Bare diagrams for explaining examples of determination of the arrangementdirection of the index values by the determination function 353according to the second embodiment. For example, in a situation similarto the situation in which the graph illustrated in FIG. 7A is obtained(in the situation in which a graph generated from the values of the FFRcalculated through fluid analysis is likely to be referred to), thedetermination function 353 makes a determination to display a graph inwhich the branched side is arranged on the lower side as illustrated inFIG. 10A.

In contrast, in a situation similar to the situation in which the graphillustrated in FIG. 7B is obtained (in the situation in which a graphgenerated from the values of the FFR measured by the FFR measurementapparatus is likely to be referred to), the determination function 353makes a determination to display a graph in which the peripheral side isarranged on the lower side as illustrated in FIG. 10B.

In the above-described first embodiment, a case has been described inwhich the FFR is displayed as the index related to blood flow. However,the embodiment is not limited to this example, and other indexes, suchas a flow rate, a flow velocity, or a pressure, may be displayed, forexample. In this case, the display orientation of a graph generated foreach index is determined, and the graph is displayed in the determineddisplay orientation.

Furthermore, in the above-described first embodiment, a case has beendescribed in which the arrangement direction of the index values isdetermined depending on an environment. In addition, the medicalinformation processing apparatus 300 may determine a display orientationin accordance with a different graph to be displayed for comparison.This will be described below.

When the display orientation is determined in accordance with adifferent graph to be displayed for comparison, the control function 351acquires a first index value, which is obtained based on fluid analysisthat is performed based on an image including a blood vessel of asubject and that is related to blood flow at each of positions in ablood vessel. That is, the control function 351 acquires the index valueobtained through the fluid analysis, as one of index values to bedisplayed for comparison. Here, the control function 351 may acquire, asthe first index value, the same index value as the index value describedin the first embodiment.

Then, the determination function 353 acquires external informationincluding a second index value related to the blood flow at each of thepositions in the blood vessel. For example, the determination function353 acquires external information including, as the second index value,a measurement result obtained through measurement performed by an FFRmeasurement apparatus. The determination function 353 may acquire, asthe second index value, various index values different from the firstindex value, rather than the above-described measurement result obtainedby the FFR measurement apparatus. For example, the determinationfunction 353 may acquire, as the second index value, a past index valueof a subject for whom the first index value has been acquired. Here, forexample, the determination function 353 may acquire, as the externalinformation, information on the second index value displayed on a windowdifferent from an application of the fluid analysis, information on thesecond index value displayed by being loaded on the application of thefluid analysis, or information on the second index value displayed on adifferent apparatus.

Then, the determination function 353 changes one of an arrangementdirection of the index values in a first graph, in which the first indexvalue at each of the positions in the long axis direction of the bloodvessel is plotted, and an arrangement direction of the index values in asecond graph, in which the second index value at each of the positionsin the long axis direction of the blood vessel is plotted, in accordancewith the other one of the arrangement directions. For example, thedetermination function 353 changes one of an arrangement direction ofthe index values in the first graph, in which the first index valuesobtained based on the fluid analysis are plotted, and an arrangementdirection of the index values in the second graph, in which the secondindex values measured by the FFR measurement apparatus are plotted, inaccordance with the other one of the arrangement directions. That is,the determination function 353 determines the display orientation of thegraphs such that the arrangement direction of the index values in one ofthe graphs matches the arrangement direction of the index values in theother one of the graphs.

A case will be described in which a graph of the FFR measured by the FFRmeasurement apparatus is acquired as the external information. In thiscase, the determination function 353 may directly acquire a measurementresult (the value of the FFR at each of positions in a blood vessel, ora graph) from the FFR measurement apparatus, or indirectly acquires ameasurement result that a different apparatus has acquired from the FFRapparatus. Then, the determination function 353 adjusts the arrangementdirections of the graphs for displaying the acquired measurement resultand the result of the fluid analysis performed by the control function351 (the graphs of the values of the FFR at the respective positions inthe blood vessel). Here, the determination function 353 changes thearrangement direction of the values of the FFR in one of the graph ofthe FFR obtained by the FFR measurement apparatus and the graph of theFFR obtained through the fluid analysis.

As described above, the display orientation of the graph displayed bythe FFR measurement apparatus in the FFR measurement using a pressurewire is opposite to the display orientation of the graph of the FFRobtained through the fluid analysis. Therefore, the determinationfunction 353 reverses the display orientation of one of the graphs suchthat the display orientations of both of the graphs (the arrangementdirections of the values of the FFR) match each other. FIG. 11A and FIG.11B are schematic diagrams illustrating examples of a change in thedisplay orientation by the determination function 353 according to thesecond embodiment. FIG. 11A and FIG. 11B illustrate processes performedby the determination function 353 to display the graph of the FFRobtained by the FFR measurement apparatus in a region R1 and to displaythe graph of the FFR obtained through the fluid analysis in a region R2.

For example, as illustrated in FIG. 11A, the determination function 353changes the arrangement direction of the values of the FFR such that thedisplay orientation of the graph of the FFR obtained through the fluidanalysis matches the graph of the FFR obtained by the FFR measurementapparatus. That is, as illustrated in the upper section of FIG. 11A, thedetermination function 353 changes the graph of the FFR obtained throughthe fluid analysis such that the display orientation matches the graphof the FFR in which the peripheral side is arranged on the left side andthe branched side is arranged on the right side. Consequently, thedisplay control function 354 displays a curved line L3 indicating an FFRmeasurement result obtained by the FFR measurement apparatus and acurved line L4 indicating an FFR analysis result obtained through thefluid analysis in the same display orientation as illustrated in thelower section of FIG. 11A.

For another example, as illustrated in FIG. 11B, the determinationfunction 353 changes the arrangement direction of the values of the FFRsuch that the display orientation of the graph of the FFR obtained bythe FFR measurement apparatus matches the graph of the FFR obtainedthrough the fluid analysis. That is, as illustrated in the upper sectionof FIG. 11B, the determination function 353 changes the graph of the FFRin which the peripheral side is arranged on the left side and thebranched side is arranged on the right side such that the displayorientation matches the graph of the FFR obtained through the fluidanalysis (the display orientation in which the branched side is arrangedon the left side and the peripheral side is arranged on the right side).Consequently, the display control function 354 displays the curved lineL3 indicating the FFR measurement result obtained by the FFR measurementapparatus and the curved line L4 indicating the FFR analysis resultobtained through the fluid analysis in the same display orientation asillustrated in the lower section of FIG. 11B.

The display control function 354 displays the first graph and the secondgraph such that the scales of the graphs match each other. Specifically,the display control function 354 displays a plurality of graphs suchthat the scales of the horizontal axes match each other. The horizontalaxis of the graph of the FFR represents a position in a blood vessel,and is indicated by, for example, a distance or the like. FIG. 12 is adiagram illustrating an example of display of a graph by the displaycontrol function 354 according to the second embodiment. For example, asillustrated in FIG. 12 , the display control function 354 displays thegraphs such that the horizontal axis of the graph of the FFR obtained bythe FFR measurement apparatus, which is displayed in the region R1, andthe horizontal axis of the graph of the FFR obtained through the fluidanalysis, which is displayed in the region 2, are adjusted so as torepresent a distance of “0 to 50 millimeters (mm)” from a measurementstart point at which the measurement using a pressure wire is started.

Furthermore, when a data collection region is different between thefirst graph and the second graph, it may be possible to omit display ofa part of data in the graph corresponding to a larger collection region,in accordance with the graph corresponding to a smaller collectionregion. For example, when the first graph displays measurement valuesfor a distance of 2 centimeters (cm) from a reference position in ablood vessel, whereas the second graph displays measurement values for adistance of 1.5 cm from the reference position in the blood vessel, itmay be possible to omit display of data for 0.5 cm on the peripheralside in the first graph to display the first graph and the second graphsuch that the display regions match each other.

Here, when the second index value is the measurement result obtainedthrough measurement performed by the FFR measurement apparatus, thedisplay control function 354 can adjust the scale of the graph based onthe measurement velocity used by the FFR measurement apparatus. Forexample, the display control function 354 can calculate a distance fromthe measurement start point by using an auto pull-back function of theFFR measurement apparatus. In the FFR measurement by the FFR measurementapparatus, it is possible to pull back a pressure wire at a constantvelocity, so that it is possible to calculate a distance from themeasurement start point based on a time in which the pressure wire ispulled back during the FFR measurement. For example, the display controlfunction 354 calculates a distance from the measurement start point tothe branched portion based on a time taken to pull back the pressurewire from a predetermined position in the blood vessel (the measurementstart point) to the branched portion. Then, the display control function354 displays, in the region R2, a graph of the values of the FFR fromthe branched portion to a position at the calculated distance in theblood vessel corresponding to the CT image data used for the fluidanalysis. Consequently, the display control function 354 can display thegraph of the FFR obtained by the FFR measurement apparatus and the graphof the FFR obtained through the fluid analysis using the CT image datasuch that the scales of the graphs match each other.

The scales of the graphs may be adjusted by other methods, instead ofthe above-described method. For example, the display control function354 displays a CT image generated from the CT image data used for thefluid analysis and accepts an operation of specifying a position in theCT image at which the FFR is measured using a pressure wire, to therebyacquire information on a blood vessel region measured by the FFRmeasurement apparatus. Then, the display control function 354 displays,in the region R2, a graph of the values of the FFR in the acquired bloodvessel region in the blood vessel corresponding to the CT image dataused for the fluid analysis.

Furthermore, the display control function 354 may adjust the scales ofgraphs and display the graphs in an overlapping manner. FIG. 13 is adiagram illustrating an example of display of a graph by the displaycontrol function 354 according to the second embodiment. For example, asillustrated in FIG. 13 , the display control function 354 can display,on a single graph, the curved line L3 indicating the FFR measurementresult obtained by the FFR measurement apparatus and the curved line L4indicating the FFR analysis result obtained through the fluid analysis.In this case, as illustrated in FIG. 13 , the display control function354 may display each of the curved lines in a distinguishable manner.For example, the display control function 354 may display the curvedlines in a distinguishable manner by displaying the curved line L4indicating the FFR analysis result obtained through the fluid analysisin a color that is not used for the FFR measurement result obtained bythe FFR measurement apparatus.

Furthermore, the display control function 354 may display, in anintensified manner, a portion in which results in a plurality of graphsare different. For example, the display control function 354 displays,in an intensified manner, a portion in which a difference between thefirst graph and the second graph exceeds a predetermined threshold. FIG.14 is a diagram for explaining an example of display by the displaycontrol function 354 according to the second embodiment. For example, asillustrated in a region R3 in FIG. 14 , the display control function 354displays, in an intensified manner, a portion in which the position atwhich the value of the FFR largely changes in the curved line L3 islargely deviated from the curved line L4. In this case, the displaycontrol function 354 calculates a distance between the position at whichthe FFR value largely changes in the curved line L3 and the position atwhich the FFR value largely changes in the curved line L4, and displaysa corresponding portion in an intensified manner when the calculateddistance exceeds a predetermined threshold.

The portion displayed in the intensified manner by the display controlfunction 354 is not limited to the above-described example, and otherportions may be displayed in an intensified manner. For example, thedisplay control function 354 may display, in an intensified manner, aportion in which the values of the FFR at the same position in thecurved line L3 and the curved line L4 are largely different. In thiscase, the display control function 354 obtains a difference between thevalue of the FFR indicated by the curved line L3 and the value of theFFR indicated by the curved line L4, and displays a correspondingportion in an intensified manner when the value of the differenceexceeds a predetermined threshold.

Furthermore, the display control function 354 may present a position onan image corresponding to a portion in which results in a plurality ofgraphs are different. Specifically, the display control function 354displays a blood vessel image, in which a blood vessel regioncorresponding to a portion in which a difference between the first graphand the second graph exceeds a predetermined threshold is intensified.FIG. 15 is a diagram illustrating an example of display by the displaycontrol function 354 according to the second embodiment. For example, asillustrated in FIG. 15 , the display control function 354 displays, inan intensified manner, a region R4 in which results in a plurality ofgraphs are different in a three-dimensional (3D) model generated basedon the CT image data used for the fluid analysis. The region of the CTimage data in which the results in the plurality of graphs are differentcan be identified based on a position in the blood vessel in whichresults obtained by calculating differences between the graphs aredifferent.

In FIG. 15 , a case has been illustrated in which the 3D model generatedbased on the CT image data is used; however, the embodiment is notlimited to this example. For example, it may be possible to use a CTimage generated from the CT image data. In this case, the displaycontrol function 354 displays a region, in which the results in theplurality of graphs are different, in an intensified manner in the CTimage. Furthermore, in FIG. 15 , a case has been illustrated in whichonly the blood vessel image (a 3D model or a CT image) is displayed;however, the embodiment is not limited to this example. It may bepossible to display a graph together with the blood vessel image.

The FFR measurement result obtained by the FFR measurement apparatusexplained in the above-described embodiments may be a result obtainedbefore an operation or a result obtained after an operation. That is,the determination function 353 may acquire the measurement resultobtained through measurement performed by the FFR measurement apparatusbefore an operation is performed on a subject, or may acquire externalinformation including, as the second index value, the measurement resultobtained through measurement performed by the FFR measurement apparatusafter an operation is performed on the subject.

Furthermore, in the above-described embodiments, a case has beendescribed in which the graph of the FFR obtained by the FFR measurementapparatus and the graph of the FFR obtained through the fluid analysisusing the CT image data are compared. However, the embodiment is notlimited to this example. For example, it may be possible to display agraph of an FFR obtained through past fluid analysis and a graph of anFFR obtained through current fluid analysis in a comparable manner. Asone example, when the graph obtained through the fluid analysisperformed in the past is recorded in a medical record in the samedisplay orientation as the graph of the FFR obtained by the FFRmeasurement apparatus, the determination function 353 may change adisplay orientation of the graph of the FFR obtained through the currentfluid analysis (the arrangement direction of the values of the FFR) tothe same orientation as the graph of the FFR recorded in the medicalrecord. Consequently, the display control function 354 displays thegraphs of the analysis results obtained through the past fluid analysisand the current fluid analysis in the same display orientation (thearrangement direction of the values of the FFR) as the graph of the FFRobtained by the FFR measurement apparatus.

Similarly, when a graph, which is obtained in the past by the FFRmeasurement apparatus, is recorded in a medical record in the sameorientation as the graph of the FFR obtained through the fluid analysis,the determination function 353 may change the display orientation of agraph of an FFR currently obtained by the FFR measurement apparatus (thearrangement direction of the values of the FFR) to the same orientationas the graph of the FFR recorded in the medical record. Consequently,the display control function 354 displays the graphs of the pastmeasurement result and the current measurement result obtained by theFFR measurement apparatus in the same display orientation (thearrangement direction of the values of the FFR) as the graph of the FFRobtained through the fluid analysis.

Furthermore, in the above-described embodiments, a case has beendescribed in which two graphs are displayed for comparison. However, theembodiments are not limited to this example. It may be possible todisplay three or more graphs in a comparable manner.

In the above-described embodiments, a case has been described in which asingle processing circuitry (the processing circuitry 350) implementsvarious processing functions; however, the embodiments are not limitedto this example. The processing circuitry 350 may be configured by acombination of a plurality of independent processors, and causes each ofthe processor to execute each of programs to implement each of theprocessing functions. In addition, the processing functions included inthe processing circuitry 350 may be appropriately distributed orintegrated, and may be implemented by a single processing circuitry or aplurality of processing circuitries.

Furthermore, the term “processor” used in the above-describedembodiments means, for example, a central processing unit (CPU), agraphics processing unit (GPU), or a circuitry, such as an applicationspecific integrated circuit (ASIC) or a programmable logic device (forexample, a simple programmable logic device (SPLD), a complexprogrammable logic device (CPLD), or a field programmable gate array(FPGA)). It may be possible to directly incorporate a program in thecircuitry of the processor, instead of storing the program in thememory. In this case, the processor reads and executes the programincorporated in the circuitry to implement the functions. Furthermore,each of the processors according to the embodiments does not necessarilyhave to be configured as a single circuitry, but may be configured as asingle processor by a combination of a plurality of independentcircuitries to implement the functions.

The program executed by the processor is provided by being incorporatedin a read only memory (ROM), a memory, or the like in advance. Theprogram may be provided by being recorded in a computer-readablerecording medium, such as a compact disk-ROM (CD-ROM), a flexible disk(FD), a CD-recordable (CD-R), or a digital versatile disk (DVD), in afile format installable or executable by the apparatus. Furthermore, theprogram may be stored in a computer connected to a network, such as theInternet, and may be provided or distributed by being downloaded via thenetwork. For example, the program is configured by modules includingrespective functional units. As actual hardware, the CPU reads theprogram from a storage medium, such as a ROM, and executes the program,so that each of the modules are loaded on a main storage device andgenerated on the main storage device.

According to at least one of the above-described embodiments, it ispossible to improve the visibility of a graph of an index related toblood flow.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A medical information processing apparatuscomprising: a memory configured to store correspondence information thatassociates types of clinical data with display directions of a long axisdirection of graphs corresponding to the types of clinical data,respectively, the types of clinical data being obtained at a pluralityof positions in a long axis direction of a blood vessel, the long axisdirection of the graphs corresponding to the long axis direction of theblood vessel; and processing circuitry configured to: perform imageprocessing on image data to generate an image of the blood vessel of asubject, acquire two types of clinical data, at least one type of thetwo types of clinical data being obtained by analyzing the image of theblood vessel of the subject, acquire type information of the two typesof clinical data by collecting incidental information of the two typesof clinical data via a network, judge, based on the correspondenceinformation stored in the memory, whether or not display directions ofthe two types of clinical data match each other, and match, inaccordance with a judgment result, the display directions of the longaxis direction of two graphs corresponding to the two types of clinicaldata with each other, and cause a display to display the two graphs withthe same display direction on the long axis direction.
 2. The medicalinformation processing apparatus according to claim 1, wherein one ofthe two graphs is obtained by analyzing the image of the blood vessel,and in which a left side in the long axis direction corresponds to abranched side of the blood vessel.
 3. The medical information processingapparatus according to claim 1, wherein one of the two graphs isobtained by performing measurements on the blood vessel of the subject,and in which a right side in the long axis direction corresponds to abranched side of the blood vessel.
 4. The medical information processingapparatus according to claim 1, wherein the type information of the twotypes of clinical data is attached to the two types of clinical data,respectively.
 5. The medical information processing apparatus accordingto claim 1, wherein the processing circuitry is configured to match,when the display directions of the two types of clinical data match eachother, scales of the two graphs with each other.
 6. The medicalinformation processing apparatus according to claim 5, wherein the typeinformation of the two types of clinical data is specified based oninformation indicating a location or a room from which the clinical datais acquired.
 7. The medical information processing apparatus accordingto claim 5, wherein the processing circuitry is configured to determinethe display direction to match based on information about an operator.8. A medical information processing system that includes a memoryconfigured to store correspondence information that associates types ofclinical data with display directions of a long axis direction of graphscorresponding to the types of clinical data, respectively, the types ofclinical data being obtained at a plurality of positions in a long axisdirection of a blood vessel, the long axis direction of the graphscorresponding to the long axis direction of the blood vessel, themedical information processing system comprising: processing circuitryconfigured to: perform image processing on image data to generate animage of the blood vessel of a subject, acquire two types of clinicaldata, at least one type of the two types of clinical data being obtainedby analyzing the image of the blood vessel of the subject, acquire typeinformation of the two types of clinical data by collecting incidentalinformation of the two types of clinical data via a network, judge,based on the correspondence information stored in the memory, whether ornot display directions of the two types of clinical data match eachother, and match, in accordance with a judgment result, the displaydirections of the long axis direction of two graphs corresponding to thetwo types of clinical data with each other, and cause a display todisplay the two graphs with the same display direction on the long axisdirection.
 9. A medical information processing method for a medicalinformation processing apparatus that includes a memory configured tostore correspondence information that associates types of clinical datawith display directions of a long axis direction of graphs correspondingto the types of clinical data, respectively, the types of clinical databeing obtained at a plurality of positions in a long axis direction of ablood vessel, the long axis direction of the graphs corresponding to thelong axis direction of the blood vessel, the medical informationprocessing method comprising: performing image processing on image datato generate an image of the blood vessel of a subject; acquiring twotypes of clinical data, at least one type of the two types of clinicaldata being obtained by analyzing the image of the blood vessel of thesubject, acquiring type information of the two types of clinical data bycollecting incidental information of the two types of clinical data viaa network, judging, based on the correspondence information stored inthe memory, whether or not display directions of the two types ofclinical data match each other, and matching, in accordance with ajudgment result, the display directions of the long axis direction oftwo graphs corresponding to the two types of clinical data with eachother, and causing a display to display the two graphs with the samedisplay direction on the long axis direction.